Photodynamic therapy (PDT) is a non-invasive medical procedure used for the treatment of various diseases. PDT involves the administration of a photosensitizing compound that concentrates around a portion of tissue. Thereafter the tissue that is concentrated with the photosensitizing compound is irradiated. The target tissue containing a sufficiently high concentration of the photosensitizing compound selectively absorbs the light which induces impairment or destruction of the immediately surrounding cells.
One disease treated with PDT is wet age-related macular degeneration. Age-related macular degeneration results in the loss of vision in the macula due to damage in the retina. The wet (or excudative) form of age-related macular degeneration occurs when blood vessels spread from the choroid behind the retina. This abnormal blood vessel growth can cause detachment of the retina. The detachment of the retina can be avoided by preventing the spread of abnormal blood vessel growth. The spread is prevented by irradiating a photosensitizing compound in a tissue that causes impairment or destruction of the surrounding cells through a cytotoxic effect. A method of PDT is described in U.S. Pat. No. 5,756,541, the entirety of which is incorporated by reference.
Typically, photosensitizing agents such as Visudyne® are used to treat the wet form of age-related macular degeneration. Visudyne® is discussed in U.S. Pat. Nos. 5,171,749, 5,095,030, 5,707,608, 5,770,619, 5,798,349, and 6,074,666, the entireties of which are incorporated by reference. Visudyne® is administered intravenously for approximately ten minutes. After approximately fifteen minutes, the treatment site is activated with laser light having a wavelength of approximately 689 nm at 150-600 mW/m2. As known to those skilled in the art, verteporfin is the generic form or equivalent of Visudyne
There are several laser systems in the prior art to deliver laser light such as Lumenis' Opal Photactivator laser console and modified Lumenis LaserLink adapter manufactured by Lumenis, Inc., Zeiss' VISULAS 690s laser and VISULINK® PDT adapter manufactured by Carl Zeiss Meditec Inc., and Quantel's Activis laser console and ZSL30 ACT™, ZSL120 ACT™, Ceralas™ I laser system and Ceralink™ Slit Lamp Adaptor manufactured by Biolitec, Inc. and HSBMBQ ACT™ slit lamp adapters distributed by Quantel Medical. These prior art laser systems have bulky control panels and are expensive and increase the costs of PDT for wet age-related macular degeneration.
Therefore, there is a need in the art for a PDT laser system to be used for treating wet age-related macular degeneration, central serous chorioretinopathy (CSC) or polypoidal chorodial vasculopathy (PCV), (subfoveal occult or classical) coroidal neovasculization (CNV), and other similar diseases which is compact, portable, easier to use in a treatment facility, and economical to manufacture.